AUTOMATIC APPARATUS FOR IN-LINE CLEANING OF MOULDS FOR

TYRES

Technical field

This invention relates to an automatic apparatus for in-line cleaning of moulds for tyres.

Current construction techniques of modern tyres, which are mounted on a huge number of vehicles of the most diverse types, involve the use of suitable moulds, normally made of aluminium alloys, of steel, or even of mixed aluminium and steel material, in which ready-made structural elements are positioned, able to give the tyre resistance to the load stresses and resistance to the inflation pressure of wheels.

The tyre is then vulcanised in a press, in which devices are mounted which contain the mould, divided into cheeks and sectors.

But when the moulds have been used a certain number of times, they have to be carefully maintained, by removing residues and attached patches of vulcanised rubber present in the small cavities of the cut surfaces and in particular in the holes which house the automatic vents. Obviously, failure to remove such fragments could result in defects and imperfections on the moulded surface of the tyre, with a consequent reduction in the production quality level.

Background art

In the prior art, in contexts of moderate production, such removal is still performed manually using equipment which launches jets of abrasive materials such as sands, shot, dry ice.

More modern automatic plants are also used which, located inside protective structures or hermetically sealed environments, use jets of various cleaning substances, which can be automatically oriented in multiple directions for completely cleaning the parts of the mould. Such plants differ substantially depending on whether they clean the moulds while they are in the line or, alternatively, require the moulds to be detachecTlrom the forming line so that they can be completely disassembled and then cleaned in steps and times that are separate from the forming operations.

For the former type of plants, the apparatus which is the subject matter of this patent application belonging to this type, it is obvious how it is important that cleaning of the moulds should take place in relatively rapid times, since said operation directly interferes with the production process. Naturally, although speed is important, it is also essential to maintain an optimum level of cleaning, at the same time excluding the use of techniques that are too invasive and not very precise, which could cause wear and damage on the moulds. Disclosure of the invention

The aim of this invention is, therefore, to reduce the limitations and eliminate the disadvantages mentioned above.

The invention, as characterised in the claims, achieves the aim by means of a robotised automatic apparatus which, acting flexibly and with extreme precision on every type of mould kept in the production line, provides optimum cleaning of it.

The main advantage of this invention is basically the fact that the moulds are cleaned rapidly and without causing wear and damage on them.

A further advantage is the fact that the automation and precision of the apparatus provide more thorough and optimised cleaning of the moulds, extending their periods of use and making use of them more economical. Another advantage of the invention is the fact that the quickness with which the moulds are cleaned and put back into operation means that it is possible to reduce the number of them required for the production expected.

Moreover, the fact that the invention comprises insulated walls for isolating the mould to be cleaned results in less noise in the working environment, thereby improving conditions for the personnel involved.

The invention also relates to a soundproofing device, in particular for cleaning apparatuses, comprising a housing provided with an electronic system equipped with at least one sensor, said electronic system being calibrated on the sound spectrum present inside said housing for cancelling out the sound waves produced inside said housing with as many sound waves having the same amplitude and inverted phase which are emitted by said at least one sensor.

Brief description of the drawings

Further advantages and features of the invention are more apparent in the detailed description which follows, with reference to the accompanying drawings, which illustrate an example of it without limiting the scope of the invention, in which:

Figure 1 is a perspective assembly view of the invention;

Figures 2 to 4 are side views in cross-section of the invention relating to a sequence of positions of use;

Figure 5 is a schematic view of a soundproofing device according to the invention;

Figure 6 shows the soundproofing device positioned on the apparatus for cleaning moulds;

Figure 7 illustrates an operating detail of the soundproofing device. Detailed description of preferred embodiments of the invention

An automatic apparatus for in-line cleaning of moulds for tyres comprises, as illustrated in the figures, the presence on the cleaning line of a tyre vulcanisation press 5 equipped with seats 5a, 5b for housing the moulds 1a, 1b.

The moulds 1a, 1b have a substantially cylindrical configuration and are spaced along a substantially vertical axis. The apparatus 10 comprises at least one nozzle 2 fed by a pressurised duct 3, suitable for sending a cleaning jet, preferably constituted of dry ice, onto the moulds 1a, 1b, and movement means 20 for moving the nozzle 2; said movement means 20 for moving the nozzle 2 comprise a support 21 , provided with a rotary arm 21a and at least one carriage 21b slidable longitudinally along the arm 21a, and an anthropomorphic manipulator robot 22, associated with the carriage 21b, which uses a control software 22a for at least eight degrees of freedom, able to guide the nozzle 2 in such a way as to clean the moulds 1a, 1b according to the tread pattern. Advantageously, the arm 21a is designed to rotate about its own axis of extension. In the embodiment illustrated axis of extension of the arm 21a is substantially perpendicular to the axis of the moulds 1a, 1 b.

Preferably, the anthropomorphic manipulator robot 22 is associated with the carriage 21b by means of a first rotary joint for rotation about an axis parallel to the axis of translation of the carriage 21 b. The manipulator robot 22 is advantageously a six-axis robot with a seventh axis angled at 45°. The control software 22a interpolates and integrates all of the axes with the various parts of the apparatus. That configuration allows substantially all of the robot 22 to be contained in the moulds 1a, 1b during the washing operation.

The apparatus also comprises detecting means 11 for detecting images of the state of the moulds 1a, 1b, in such a way that they are also cleaned based on the images detected, as well as on the tread pattern. In one possible embodiment of the invention, schematically illustrated in Figures 2 and 4, said detecting means 11 are constituted of a movable electronic micro-camera, able to capture images of the moulds 1a, 1 b before and after the cleaning action of the nozzle 2, so that it is possible to compare their degree of cleanness obtained with a predetermined standard.

As illustrated in the figures, the apparatus also comprises confining means , 41 for the movement means 20 and the nozzle 2, designed to isolate the cleaning zone. Said confining means 41 comprise a longitudinal element 41a removably associated with the support 21 , containing the sliding carriage 21b and the robot 22 connection, and also comprise a cylinder 41b with a vertical axis, securely joined to the element 41a, suitable for containing the nozzle 2 and the end part of the robot 22.

Said cylinder 41b comprises a closing base 42 at one end, and at the other end a cylindrical projection or offshoot 43 telescopically associated with the element 41b. By making the offshoot 43 slide, it is possible to adjust the height of the cylinder 41b according to the various types of moulds 1a, 1b and the various cleaning steps.

The invention comprises a soundproofing device for acoustically isolating the mould cleaning zone.

The soundproofing device is advantageous in particular with the use of dry ice during the cleaning operation. In fact, since the dry ice dispensing nozzle has a considerable spraying pressure and generates continuous micro-explosions due to the big temperature difference between the dry ice (-70C°) and the mould (+190C), the noise of that technology is high (approximately 180 decibels).

The soundproofing device according to the invention is based on the ANC, Active Noise Control, method also known as noise cancellation, or ANR, Active Noise Reduction, for reducing unwanted sound by superimposing a second sound specifically designed to cancel out the first.

According to that method, a sound wave is emitted having the same amplitude and inverted phase compared to the external sound to be cancelled out. The wave emitted and the external noise combine in a process called interference and cancel each other out.

As illustrated in Figure 5, the soundproofing device comprises a housing 44 provided with an electronic system 45 equipped with at least one sensor 46. The system 45 is designed to cancel out the sound waves produced and emitted by the impact of the cleaning material against the moulds, for example by the explosions of the dry ice in contact with the hot surface of the segments of moulds to be cleaned, with as many sound waves having the same amplitude and inverted phase which are emitted by the sensor 46 or by the sensors of the electronic device. The electronic system 45 is calibrated on the sound spectrum generated by the impact of the cleaning material against the moulds. In the case of dry ice, the electronic system makes it possible to reduce the noise from approximately 180 decibels to less than 80 decibels.

In the embodiment illustrated in Figures 5 and 6, the housing 44 is substantially cylindrical and is designed to be positioned inside the cylinder 41b.

The housing 44 is provided with a cavity 47 in which a plurality of sensors 46 is positioned in such a way as to create in the space inside the housing 44 a very dense network of sound waves having the same amplitude and inverted phase compared to those created by operation of the nozzle 2 during the cleaning operation.

Preferably, the cavity 47 is approximately 5 cm and is designed to contain, in addition to the sensors 46, the junction wiring, advantageously protected and immersed in a refractory insulating material able to withstand high temperatures, and the connections to the control software. As is schematically illustrated in Figure 6, operation of the electronic system 45 is given by the positioning of the sensors 46, since each sensor 46 generates sound waves within a cone of action, in such a way as to create inside the cylindrical housing 44 a dense network of sound waves with a frequency that is the same but inverted compared to that derived from the explosion of the dry ice. In this way, it is easier for the sound waves that must be cut to be intercepted by the inverted sound waves created by the sensors.

Finally, the apparatus comprises positioning means 30 for the movement means 20, for positioning them according to the various types of moulds 1a, 1 b and the various cleaning steps. - ,

As illustrated in Figure 1 , said positioning means 30 comprise at least a translating lift truck 31 , equipped with a movable frame 31a and associable, preferably removably, with the arm 21a of the support 21 , in such a way that it can move the nozzle 2 movement means 20 into the various positions required for cleaning the moulds 1a, 1b. The positioning means 30 also comprise at least one spacer ring 32, suitable for keeping the cylinder 41b raised for each type of mould 1a, 1b, as illustrated in Figures 2 and 3.